Christopher Hearty, Assistant Professor/IPP Research Scientist

B.Sc. Simon Fraser University (82)
Ph.D. University of Washington (87)
Postdoctoral Researcher, Lawrence Berkeley Laboratory (87-94)

Hennings 268
604 822 9163 or 604 221 3228 (TRIUMF)
hearty@physics.ubc.ca

more photos

(All images are linked thumbnails)

Research Interests

I am studying the physics of weak interactions as a member of the BaBar collaboration, which is located at the Stanford Linear Accelerator Center in California. The most exciting aspect of the BaBar physics program is the study of the origins of CP-violation. CP (charge-parity) is a symmetry that relates matter to antimatter. Given that the observed universe is made of matter, it is clear that CP is violated. Laboratory studies of the decays of neutral K mesons in 1964 demonstated CP violation, but did not reveal the underlying cause of the asymmetry. BaBar has recently established that CP is violated in B mesons as well, the first such observation outside of the Kaon system. The Toronto Star wrote a feature science article on our discovery.

I am the Principal Investigator of the Canadian BaBar group, which includes seven faculty members, four research associates and ten graduate students. Overall, there are about 400 physicists working on BaBar! But there is lots of exciting physics to work on. I have been studying the production of Charmonium mesons (made of a charm quark/anti-quark pair) with Marko Milek, who just received his PhD from McGill. We discovered that they are produced directly in e+e- annihilations, a result that sheds light on how Quantum Chromodynamics (QCD) works. One other paper has been submitted for publication, and a third is in the works.

I am now starting to work on rare decays of the B. BaBar has a huge sample of B's and is rapidly getting more, so we will be able to do an excellent job in this area. The idea is to study processes that are strongly suppressed in the Standard Model of particle, where small additional signals from new physics will be clearly visible.

Students

Here are some students who have worked with me recently. I am interesting in taking on new graduate students and have listed a few of the possible thesis projects below.

	Nasim Boustani: Development of the phi gamma control sample
	Mark Milek: (PhD at McGill): Charmonium production at BaBar
	Dan Giang: Search for the rare decay B --> K nu nu-bar
	Marie-Helene Genest: Determination of the number of Upsilon(4S) mesons in the BaBar run1 data
	James Griffiths: Selection of two-photon-produced muons pairs as a muon-identification control sample
	Angela O'Neill: Non-flammable gases for the BaBar drift chamber
	Robin Stoodley: Drift chamber assembly
	Wesley Philip Wong: Development of drift chamber assembly techniques

Thesis Topics

Here are a few possible thesis topics. Some are suitable for an MSc; others for a PhD. Please contact me for additional information.

Search for the rare penguin decay B --> K neutrino anti-neutrino.
Measurement of B --> tau neutrino.
Search for the rare decay B --> K gamma
Selection and production of the control samples e+e- --> gamma phi and gamma omega.
Study of muon identification algorithms and muon detector simulation using two-photon produced muon pairs.
Analysis of Psi2s and chi_c production in e+e- annihilations.
Determination of the Upsilon(4S) resonance shape.

Drift Chamber Construction

A major part of the BaBar detector, the Drift Chamber, was built at TRIUMF as the Canadian contribution to the hardware. I oversaw its construction and was the run coordinator during the first commissioning run of BaBar. Here are some photos:

Overview of stringing in the clean room

Putting on the outer cylinder

Chamber arriving at SLAC

Inserting it into BaBar

Selected Publications

Observation of CP violation in the B0 meson system, B. Aubert et al, Phys. Rev. Lett. 87, 091801 (2001).
Measurement of J/psi production in continuum e+e- annihilations near sqrt(s) = 10.6 GeV, SLAC-PUB-8854, Phys. Rev. Lett. 87, 162002 (2001).
Measurement of the branching fractions for psi(2s) --> e+e- and psi(2s) --> mu+mu-, SLAC-PUB-8953 (2001). Submitted to Phys. Rev. D (rapid communication).
The BABAR detector, B. Aubert et al, SLAC-PUB-8569 (2001). To appear in Nuclear Instruments and Methods.
Measurement of CP-violating asymmetries in B0 decays to CP eigenstates, B. Aubert et al, Phys. Rev. Lett. 86 (2001) 2515-2522.